diff --git a/lib/fluent/event.rb b/lib/fluent/event.rb
index 97711f4621..98893351a2 100644
--- a/lib/fluent/event.rb
+++ b/lib/fluent/event.rb
@@ -49,7 +49,7 @@ def slice(index, num)
       raise NotImplementedError, "DO NOT USE THIS CLASS directly."
     end
 
-    def each(unapcker: nil, &block)
+    def each(unpacker: nil, &block)
       raise NotImplementedError, "DO NOT USE THIS CLASS directly."
     end